The BGP router must be configured to reject outbound route advertisements for any prefixes that do not belong to any customers or the local autonomous system (AS).

Associated with: CCI-001368

SV-92979r1_rule The BGP router must be configured to reject outbound route advertisements for any prefixes that do not belong to any customers or the local autonomous system (AS).

Vulnerability discussion

Advertisement of routes by an autonomous system for networks that do not belong to any of its customers pulls traffic away from the authorized network. This causes a denial of service (DoS) on the network that allocated the block of addresses and may cause a DoS on the network that is inadvertently advertising it as the originator. It is also possible that a misconfigured or compromised router within the GIG IP core could redistribute IGP routes into BGP, thereby leaking internal routes.

Check content

Review the router configuration to verify that there is a filter defined to only advertise routes for prefixes that belong to any customers or the local AS. The prefix filter must be referenced outbound on the appropriate BGP neighbor statements. If the router is not configured to reject outbound route advertisements that belong to any customers or the local AS, this is a finding.

Fix text

Configure all eBGP routers to filter outbound route advertisements for prefixes that are not allocated to or belong to any customer or the local AS.

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